Heretofore from the Polish patent description no. 149887 there is known a method of obtaining liquid fuels from atactic polypropylene, according to which raw material is subjected to a thermodegradation process at temperatures between 180.degree. C. to 340.degree. C., introducing air into a reaction system. During the process according to the known method the fractionated reception and condensation of products are kept.
European patent application no. 0577279 A1 teaches a method of polymer processing, which is based on thermal decomposition of polyolefines, poly/vinyl chloride/ and poly/ethylene terephtalate/ at temperatures from 300.degree.C. to 600.degree. C. in a stream of a hot gas free of oxygen. The process runs in the presence of a catalyst in a form of zeolytic clay, amorphic aluminium silicate, silica, quartz, aluminium, zirconium, ash and calcium oxide.
In the above method, the use of a fluidized reactor is necessary. The resultant products are characterised in a broad range of a molecular weight distribution.
U.S. Pat. No. 4,584,421 teaches a method of decomposition of polyolefines wastes, based on heating a melted reaction mass up to temperatures between 440.degree.C.-470.degree. C. in the presence of catalyst. In the mentioned temperatures volatile products are obtained, which are consequently introduced into a catalyst bed of a temperature between 350.degree. C.-470.degree. C., after which hydrocarbons of a narrow range of molecular weight are formed.
The catalyst belongs to the group of compounds, comprising ferrous-aluminium oxide complex, silicic acid-ferrous oxide complex and zeolites. The products, obtained according to the known methods have a broad range of molecular weights.